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11  Id 


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GIFT   OF 
Arthur  E.   Moncaster 


lEe 

Westinghouse-Leblanc 
Condenser 


A  description  with 

suggestions  and  instructions 

for  its 


INSTALLATION 

CARE  AND 

OPERATION 


ENGINEER'S  REFERENCE  BOOK 

Please  keep  this  book  where  your  engineer  can  refer 

to  it  readily 


Instruction  Book,  WM 102— Second  Edition 


August,  1910 


The  Westi  n  dhouse 


lEe 

Westinghouse-Leblanc 
Condenser 


A  description, 

with  suggestions  and  instructions 
for  its 


INSTALLATION 


CARE  AND 


OPERATION 


EAST    PITTSBUR.C.PA. 


\VESTINGHOUSE-I<ICBI<ANC   CONDENSER    WITH   STEAM   TURBINE  DRIVE 


THE  WESTINGHOUSE-LEBLANC 
CONDENSER 

The  Westinghouse-L-eblanc  Condenser  represents  the 
highest  development  of  that  class  of  condensing  apparatus 
known  as  the  jet  type.  In  most  phases  of  modern  engineering 
a  radical  improvement  in  economy  or  efficiency  is  attained  by 
increased  complication  or  addition  of  parts.  In  the  case  of  the 
Leblanc  condenser  the  improvement  in  efficiency  has  been 
attained  in  a  less  complicated  machine. 

There  are  no  rubbing  parts  except  the  bearings  and 
packing  glands.  There  are  no  reciprocating  parts,  no  valves 
in  the  pumps,  nor  are  there  any  parts  requiring  lubrication 
other  than  the  bearings. 

The  Prime  Advantages  of  the  Leblanc  Condenser  are: 

1.  The  striking  simplicity  of  the  apparatus,  and  con- 
sequent ease  of  manipulation  and  operation. 

2.  The  extraordinary  efficiency  as  compared  with  other 
types  of  jet  condensers. 

3.  The  absence  of  internal  rubbing  parts,  so  that  wear 
is  eliminated,  and  consequently  the  efficiency  does  not  drop  off 
after  long  periods  of  operation. 

4.  The  concentration  of  all  of  the  moving  parts  of  the 
apparatus  on  a  single  revolving  shaft 

5.  The  adaptability  for  direct  driving  by  a  steam  turbine 
or  electric  motor — either  of  which  represents  the  utmost  possi- 
bilities in  the  way  of  simplicity  and  reliability. 

General  Description 

Figure  i  shows  a  sectional  view  of  a  condenser.  In 
general  it  consists  of  a  chamber  with  means  for  admitting  the 
steam  and  water,  and  intimately  mixing  them.  The  condensed 
steam  and  water  are  then  discharged  by  means  of  a  properly 
designed  centrifugal  pump.  The  air  not  entrained  with  the 
water  is  taken  off  by  a  special  turbine  air  pump. 


Referring  to  the  illustration,  the  injection  water  enters 
at  A,  by  virtue  of  the  vacuum  within  the  condenser,  and  is 
drawn  through  the  induction  passages  B-B-B. 

It  then  meets  and  is  intimately  mixed  with  the  exhaust 
steam,  which  has  entered  either  at  the  top  or  side  inlet  on  the 
condenser  head.  The  mixture  of  condensed  cteam  and  water 
drops  through  the  large  combining  cone  into  the  chamber  K, 
and  is  discharged  by  the  centrifugal  pump  F.  If  desired,  this 
pump  can  be  proportioned  to  deliver  the  hot  water  to  the  top  of 
a  cooling  tower  or  through  spray  nozzles,  or  against  any  pres- 
sure such  that  the  head  imposed,  including  friction,  is  not  more 
than  50  feet  above  the  condenser  base. 

It  will  be  noted  that  the  nozzle  plate  C,  can  be  swung 
into  the  position  shown  in  dotted  lines  so  that  any  debris  that 
may  have  lodged  there  can  be  cleaned  out.  Access  to  this  plate 
may  be  had  through  manholes  on  the  side  of  the  top  chamber. 

These  nozzles  have  liberal  passages,  and  if  proper  screens 
or  strainers  are  placed  in  the  water  intake  it  should  not  be 
necessary  to  clean  them. 

The  air  pump  draws  its  air  through  the  pipe  K.  Note 
the  sectional  view  of  the  air  pump  to  the  right  in  Figure  i.  To 
start  the  air  pump  in  operation  high  pressure  steam  is  turned 
into  the  connection  L.  The  cone  near  L  forms  the  annular 
nozzle  of  a  steam  ejector,  so  that  on  opening  the  valve  in  the 
steam  line  to  L,  a  vacuum  is  created  in  the  body  of  the  air 
pump.  The  chamber  G  being  piped  up  to  a  source  of  water 
supply  is  immediately  filled  on  account  of  the  vacuum  created 
by  the  steam  ejector.  Water  then  flows  through  the  distri- 
buting nozzle  H,  and  is  projected  in  layers  in  a  downward 
direction  through  the  combining  passages  into  the  diffuser  J. 
Between  the  successive  layers  of  water,  layers  of  air  are  impris- 
oned, these  layers  of  water  (on  account  of  the  high  peripheral 
speed  of  the  turbine  wheel  which  throws  them  downwards) 
have  a  velocity  sufficient  to  enable  them  to  overcome  the  pres- 
sure of  the  atmosphere  and  force  their  way  out  of  the  pump  in 
which  a  high  vacuum  exists.  The  layers  of  water  act  like  a  suc- 
cession of  water  pistons  with  large  volumes  of  air  between  them. 

In  the  elbow  on  the  top  of  the  pipe  K,  there  is  a  valve 
controlled  by  a  copper  float  on  the  inside  of  the  condenser 

5 


chamber.  Should  the  water  for  any  reason  rise  as  high  as  the 
float  this  valve  will  open  and  by  admitting  air,  lower  the  vacu- 
um so  that  no  more  water  will  be  drawn  into  the  condenser. 

This  vacuum  breaker  is  placed  on  the  condenser  for 
imforseen  emergencies  only,  as  for  example,  the  accidental 
shutting  down  of  the  pump  by  an  inexperienced  attendant,  etc. 
In  general  this  arrangement  will  prevent  flooding  of  the  con- 
denser for  any  external  cause  whatsoever. 

The  vacuum  breaker  float  is  so  situated  that  under 
usual  operating  conditions  it  is  never  in  contact  with  the  water. 
It  is  immersed  only  in  emergencies  such  as  have  just  been 
mentioned. 

Just  above  the  copper  float  is  the  condenser  cone,  see  Fig. 
i,  which  acts  like  a  hood  and  shields  it  from  the  erosive  action 
of  the  water.  The  float  is  therefore  a  wholly  reliable  piece  of 
apparatus,  its  movements  are  positive,  and  its  action  certain. 


Fig.  2 

MOVING   PARTS   OF  WESTINGHOUSE-LEBLANC   CONDENSER 


Figure  2  shows  all  of  the  moving  parts  of  the  Leblanc 
condenser.  Both  parts,  the  centrifugal  and  air  pump  rotors, 
are  on  a  common  shaft,  making  a  construction  that  in  point  of 
simplicity  is  absolutely  elemental. 

In  case  of  salt  water  or  impure  water  full  of  chemical 
matter,  the  pump  runners  are  made  of  bronze  and  the  shaft 
also  thereby  thoroughly  protecting  the  pump  from  any  cor- 
rosive action. 

6 


Installation  of  the  Westinghouse-Leblanc  Condenser 

The  condenser  is  constructed  with  both  a  side  and  a  top 
inlet  for  the  admission  of  steam.  A  blank  flange  is  supplied  so 
that  the  unused  inlet  may  be  closed  off. 

The  condenser  is  preferably  installed  with  the  steam 
entering  the  side.  This  arrangement  usually  works  out  to  the 
best  advantage,  as  it  adapts  itself  excellently  to  the  most  de- 
sirable power  plant  layouts. 


ENGINE  ROOM 
FLOOR    LINE. 


EXHAUST  TO 
ATMOSPHERE. 


RELIEF  VALVE 


Fig.   3 
SHOWING   EXHAUST   CONNECTED   TO   SIDE   INLET 

In  Figure  3,  it  will  be  noted  that  when  installed  so  that 
the  steam  enters  at  the  side  inlet,  the  condenser  is  thoroughly 
accessible.  By  having  a  trap  door  in  the  engine  room  floor  the 
erection  can  be  carried  on  by  means  of  the  engine  room  crane, 
and  any  part  of  the  condenser  can  be  disassembled  by  the  same 
means  if  it  should  ever  be  necessary  to  do  so. 

Figure  4  represents  an  arrangement  in  which  the  con- 
denser is  located  beneath  the  turbine,  steam  entering  through 


the  top  inlet.  This  is  an  excellent  arrangement  but  requires 
greater  vertical  height  to  accommodate  the  condenser,  and,  of 
course,  makes  the  erection  work  more  difficult.  The  condenser 
must  always  be  in  place  before  the  turbine  can  be  erected. 


ENGINE  ROOM 
FLOOR   LINE. 


GATE  VALVE. 


Fig.   4 
SHOWING  EXHAUST  CONNECTED  TO   TOP  INLET 

It  is  not  as  accessible  as  in  the  arrangement  shown  in 
Figure  3,  and  in  case  it  were  necessary  to  make  a  repair  (say 
for  example,  on  the  expansion  joint  between  the  turbine  and 
the  condenser),  it  would  be  practically  necessary  to  lift  the  tur- 
bine of!  its  foundation  to  remove  this  expansion  joint. 

Location  of  Hot  and  Cold  Wells 

The  usual  and  most  convenient  arrangement  is  that 
shown  in  Figs.  5  and  6.  The  cold  well  should  be  located  as 
close  as  possible  to  the  condenser,  and  in  no  case  should  it  have 

8 


to  lift  the  injection  water  more  than  18  feet,  as  indicated  in 
Fig.  5.  In  case  the  cold  well  is  considerably  distant  from  the 
condenser,  the  lift  should  be  made  still  less  as  the  piping  will 
offer  a  certain  amount  of  resistance  to  the  flow  of  the  water. 


DISCHARGE  TO 

HOT  WELL. 


ENGINE  ROOM 
FLOOR   LINE. 


EXHAUST  TO 
ATMOSPHERE. 


RELIEF  VALVE. 


INLET  TO  WELL 


SUBMERSED  NOT 
LESS  THAN  3  FT. 


Fig.  5 
GENERA^  ARRANGEMENT  OF  CONDENSER  AND  CONNECTIONS 

The  air  pump  should  always  draw  water  from  the  cold 
well  and  may  if  desired,  discharge  back  into  the  source  of  sup- 
ply, as  the  water  in  passing  through  the  pump,  is  not  materi- 
ally heated.  If  the  supply  of  water  is  ample,  the  air  pump 
may  discharge  into  the  hot  well. 

There  will  be  installations  in  which  it  will  be  impracti- 
cable to  locate  the  cold  well  in  close  proximity  to  the  condenser. 
As  stated  before,  it  is  usually  desirable  to  allow  the  air  pump 
to  discharge  into  the  cold  well,  as  in  normal  operation  the  air 
pump  uses  about  15%  as  much  water  as  the  condenser  proper, 

9 


10 


and  in  a  single  passage  through  the  air  punip,  the  tempera- 
ture of  the  water  is  not  raised  more  than  y2  degree  Fahrenheit. 
In  some  cases  the  cold  well  is  of  necessity  located  higher  than 
the  base  of  the  condenser,  so  that  the  air  pump  will  have  to 
discharge  against  a  head.  It  is  possible  to  have  this  head  as 
much  as  12  feet.  This  should  not  be  exceeded  unless  the  air 
pump  is  especially  constructed  to  meet  the  specific  conditions. 
Such  an  arrangement  is  illustrated  in  Fig.  7. 

In  case  it  is  not  feasible  to  carry  the  air  pump  dis- 
charge to  either  the  hot  or  cold  well,  a  pit  adjacent  to  the 
condenser  may  be  utilized  for  the  air  pump.  The  air  pump 
will  draw  water  from  and  will  discharge  back  into  this  pit. 
While,  as  stated  above,  the  water  in  a  single  pass  through 
the  air  pump  is  not  heated  more  than  y2  degree  Fahrenheit, 
when  used  over  and  over  its  temperature  will  gradually  rise  to  a 
point  where  the  air  pump  will  not  be  able  to  operate  with  max- 
imum efficiency.  Therefore,  if  the  air  pump  draws  its  water 
from  and  discharges  it  back  into  the  same  pit  it  is  necessary 
to  bleed  a  small  amount  of  cold  make-up  water  into  the  pit  to 
keep  the  temperature  down.  If  water  under  pressure  is  not 
available,  it  may  be  taken  from  the  main  injection  line  (see 
Fig.  8).  The  air  pump  suction  valve  may  be  throttled  to  such 
an  extent  that  the  vacuum  between  it  and  the  pump  will  be 
sufficient  to  draw  water  over  from  the  main  injection.  This 
of  course,  will  tend  to  gradually  fill  the  pit,  so  that  an  overflow 
should  be  provided  at  such  a  level  that  the  air  pump  discharge 
cannot  be  submerged. 

In  case  it  is  not  possible  to  drain  the  pit,  a  connection 
controlled  by  a  float  valve  can  be  made  between  the  pit  and 
the  condenser  body.  The  condenser  will  then  draw  out  just 
the  same  quantity  of  water  that  is  let  in  by  the  make-up  line. 
This  arrangement  is  also  illustrated  in  Fig.  8. 

For  this  last  described  arrangement  adjustments  will 
have  to  be  made  with  the  valves  in  the  air  pump  suction  line, 
and  the  valve  in  the  air  pump  make-up  line.  The  valve  in 
the  make-up  line  should  be  opened  wide,  then  a  position  of 
the  valve  in  the  air  pump  suction  must  be  found  that  will 
cause  just  enough  water  to  be  drawn  over  through  the  make- 
up line  to  keep  the  temperature  of  the  water  in  the  pit  not  more 

11 


12 


RELIEF  VALVE. 


DISCHARGE  TO 

HOT    WELL. 


ENGINE  ROOM 
FLOOR   LINE. 


EXHAUST  TO 
ATMOSPHERE. 


WATER  AND  VACUUM   PUMP. 


Fig.  8 
SPECIAL  ARRANGEMENT  OF  INDEPENDENT  WEU,   FOR  AIR   PUMP 

than  2  degrees  higher  than  that  of  the  main  injection  water. 
Should  the  pit  show  a  tendency  to  overflow,  the  valve  in  the 
make-up  line  should  be  slightly  closed. 

In  cases  where  an  air  pump  pit  is  used,  the  pit  must 
be  ample  in  size.  It  must  be  remembered  that  the  water 
coming  from  the  air  pump  is  heavily  charged  with  air,  as  all 
the  air  pumped  out  of  the  condenser  is  mixed  with  the  water 
discharged  from  the  air  pump  diffuser. 

The  suction  intake  to  the  air  pump  should  be  not  less 
than  ten  feet  away  from  the  diffuser  discharge  and  be  sub- 
merged beneath  the  water  surface  by  at  least  four  feet.  The 
pit  should  be  so  proportioned  that  in  case  the  whole  cubical 
contents  of  condenser  were  drained  into  it,  it  would  not  over- 
flow. 

13 


Where  the  condenser  is  to  operate  with  salt  water  we 
do  not  advise  the  adoption  of  the  arrangement  above  described 
and  shown  in  Fig.  8,  unless  extra  precautions  are  resorted  to 
to  separate  the  air  held  in  solution  in  water  discharged  from 
air  pump.  At  least  8  feet  submergence  of  suction  should  be 
maintained  and  baffles  placed  in  the  pit  to  make  the  water 
travel  in  a  circuitous  path  so  that  the  air  may  have  ample 
time  to  liberate  itself  from  the  water.  All  this  is  necessary 
on  account  of  the  persistence  with  which  air  remains  in 
solution  in  salt  water. 

Strainers 

While  the  condensers  are  designed  with  passages  suf- 
ficiently large  to  pass  the  foreign  matter  ordinarily  found  in 
the  water,  it  is  desirable  to  have  a  strainer  in  the  injection 
line  to  prevent  the  entrance  of  such  large  bodies  as  sticks, 
stones,  etc.  A  grating  or  strainer  in  the  injection  line 
having  about  ^ "  mesh  will  effectively  prevent  the  clogging 
of  the  condenser  parts. 

Care  and  Attendance 

In  general,  the  Leblanc  condenser  needs  less  attention 
than  any  other  type  of  condenser  designed  for  high  vacuum 
service.  All  movement  is  rotary  without  rubbing  parts,  so 
that  lubrication  is  necessary  for  the  bearings  only.  There 
are  no  valves  in  either  the  air  pump  or  the  water  pump,  so 
that  the  usual  condenser  troubles  resulting  in  loss  of  vacuum 
due  to  leaky  valves  are  entirely  eliminated.  The  inherent 
efficiency  of  the  Leblanc  Condenser  will  not  fall  off  after  long 
periods  of  operation  as  is  the  case  with  condenser  systems 
where  reciprocating  air  pumps  are  used,  reciprocating  pumps 
being  subject  to  losses  due  to  leaking  valves,  worn  piston 
rings,  etc. 

After  reading  the  above  statements  and  referring  to 
previous  pages  showing  the  general  construction  of  the  con- 
denser, it  is  readily  seen  that  the  care  of  the  mechanical 
operation  is  limited  to  seeing  that  the  glands  are  kept  tight 
and  sealed  with  water  and  that  the  bearings  are  properly 

14 


Fig.  9 

SECTION   THROUGH   WATER-SEALED   GI,AND 

lubricated.  A  sectional  cut  of  the  gland  is  shown  on  page 
15,  Fig.  9.  It  is  essential  that  these  glands  be  water  sealed 
through  the  tapped  connection  shown.  In  repacking,  care 
must  be  taken  that  the  brass  distance  piece  "A"  be  kept 
practically  central  in  the  stuffing  box,  so  that  it  is  in  proper 
position  to  distribute  the  sealing  water  all  around  the  shaft. 
Clear  water  only  should  be  used  in  this  seal  as  with  dirty 
water  sediment  would  be  deposited  in  the  packing,  and  this 
gritty  deposit  will  in  time  cut  the  shaft. 

The  bearings  are  ring  oiled,  there  being  two  oil  rings 
to  each  bearing.  Sufficient  oil  should  be  poured  into  the 
bearings  to  insure  copious  lubrication  and  the  supply  should 
be  renewed  when  required.  In  continuous  station  operation 
of  any  high  duty  vacuum  apparatus  air  leaks  should  be 
eliminated  to  the  utmost  degree  possible.  Methods  of  detect- 

15 


ing  leaks  and  their  probable  location  will  be  covered  in  later 
pages. 

In  case  the  condenser  is  installed  where  the  water  level 
of  the  source  of  injection  constantly  varies,  it  is  desirable  to 
place  a  vacuum  gauge  in  the  main  injection  line  and  in  the 
air  pump  suction  line.  These  gauges  should  be  located 
between  the  condenser  and  the  valves  in  their  respective 
lines,  and  both  injection  valves  should  be  adjusted  for  varia- 
tion in  water  level  as  described  on  pages  20  and  2 1 . 

Starting  the  Condenser 

i 

Case  i.  Where  there  is  an  exhaust  valve  between  the 
turbine  or  engine  and  the  condenser. 

Case  2.  When  there  is  no  exhaust  valve  between  en- 
gine or  turbine  and  the  condenser  and  where  there  is  no 
source  of  water  under  pressure  for  priming  the  condenser. 

Case  3.  Where  there  is  no  exhaust  valve,  but  where 
there  is  a  supply  of  water  under  pressure  for  starting 
condenser. 

Case  1 

Close  the  exhaust  valve  between  the  turbine  or  engine 
and  condenser,  open  the  main  injection  valve  to  the  condenser 
a  few  turns;  open  the  air  pump  suction  valve  wide;  get  pumps 
up  to  speed  and  in  case  of  a  turbine  drive  make  sure  that 
before  admitting  steam  to  small  turbine  driving  pumps  that 
all  drains  on  the  steam  line  have  been  opened  and  the  lines 
drained;  turn  on  the  water  seal  to  the  condenser  pump  shaft 
glands,  and  open  the  steam  primer.  The  vacuum  created  by 
the  primer  will  immediately  bring  water  to  the  air  pump  and 
the  primer  should  be  opened  wide  and  kept  so  for  half  a 
minute  even  though  the  air  pump  has  gotten  its  water.  This 
will  augment  the  vacuum  and  get  the  whole  installation 
under  a  high  vacuum  in  a  very  short  space  of  time.  In  fact, 
on  the  condenser  test  floor  this  vacuum  will,  in  less  than  two 
and  one-half  minutes,  be  within  half  an  inch  of  the  highest 
vacuum  obtainable. 

16 


In  cases  where  there  are  motors  or  generators  or  high 
tension  wires  above  the  air  pump  discharge,  it  will,  of  course, 
be  unwise  to  keep  this  priming  line  open  any  longer  than  is 
just  necessary  to  get  the  water  to  the  air  pump,  as  the  free 
steam  would  rise  and  dampen  the  electrical  apparatus.  After 
the  air  pump  has  once  gotten  its  water  it  will  easily  pull  the 
vacuum  up  the  rest  of  the  way  but  not  quite  as  rapidly  as 
with  method  of  procedure  described  in  the  paragraph  next 
preceding. 

When  the  vacuum  has  risen  to  about  25"  or  26"  the 
main  injection  valve  which  was  only  slightly  opened  should 
be  opened  until  the  condenser  is  circulating  the  proper  amount 
of  water.  The  exhaust  valve  can  now  be  opened  and  the  main 
unit  which  has  been  warming  up  or  running  non-condensing 
can  exhaust  into  the  condenser.  The  atmospheric  relief  valve, 
of  course,  should  be  closed  and  its  water  seal  turned  on. 

Case  2 

There  are  some  installations  in  which  no  valve  is  pro- 
vided between  the  steam  engine  or  turbine  and  the  condenser. 

In  such  cases  the  condenser  cannot  be  started  when  the 
main  engine  or  turbine  is  in  operation,  since  the  condenser 
would  be  filled  with  exhaust  steam  and  water  must  be  drawn 
into  the  condenser  to  condense  this  steam  before  vacuum  can 
be  created.  But  the  water  will  not  be  drawn  into  the  condenser 
until  the  vacuum  exists,  so  that  it  is  manifestly  impossible 
to  start  when  the  main  unit  is  pouring  exhaust  steam  into  the 
condenser. 

It  will  therefore  be  readily  seen  that  the  main  unit  (tur- 
bine or  engine)  must  be  shut  down  when  the  condenser  is  be- 
ing started  and  furthermore  that  the  stuffing  boxes  or  glands 
on  the  shafts  or  piston  rods  must  be  tight  against  air  leakage 
when  the  machine  is  at  rest.  That  class  of  turbines  which  use 
centrifugal  water  sealed  glands  which  are  tight  only  when 
running,  are  not  well  adapted  to  this  kind  of  installation. 

In  a  general  way  it  is  a  disadvantageous  arrangement, 
since  if  for  any  reason  the  vacuum  is  lost,  the  engine  or  tur- 
bine must  be  shut  down  before  the  condenser  can  again  be  put 


in  operation.  This  objection,  of  course,  is  not  applicable 
in  the  case  of  low  pressure  turbines  as  they  are  inoperative 
any  way  when  the  vacuum  is  lost,  and  they  are  nearly  always 
equipped  with  glands  that  are  air  tight  when  the  turbine  is 
at  rest. 

With  the  engine  or  low  pressure  turbine  not  operating, 
the  procedure  of  starting  will  be  the  same  as  for  Case  i. 

Case  3 

When  there  is  no  exhaust  valve  but  where  there  is  a 
supply  of  water  under  pressure  for  starting  the  condenser. 

In  this  case  the  condenser  may  be  set  in  operation  while 
the  main  unit  is  running  non-condensing,  either  with  or  with- 
out load. 

With  no  gate  valve  between  the  main  unit  and  the 
condenser,  and  the  main  unit  operating  non-condensing,  the 
condenser  would  be  full  of  steam,  as  described  in  Case  2. 
However  with  a  supply  of  water  under  pressure  to  enter  the 
condenser  and  condense  the  steam  a  vacuum  is  quickly  created. 
With  the  vacuum  once  created,  the  condenser  will  draw  its 
own  water  and  can  go  into  regular  operation. 

The  procedure  of  starting  would  be  as  follows: — 

Bring  the  pump  up  to  speed;  turn  on  the  water  seal  to 
shaft  glands;  open  wide  the  air  pump  injection  water  valve; 
adjust  atmospheric  relief  valve  for  running  condensing;  close 
condenser  injection  valve  and  open  the  water  pressure  line 
that  is  connected  to  the  main  injection  between  the  condenser 
and  injection  valve.  The  water  under  pressure  will  immedi- 
ately create  a  partial  vacuum  which  may  be  sufficient  to  prime 
the  air  pump,  and  if  not,  open  the  steam  primer  in  the  regular 
way,  after  the  injection  is  opened. 

In  case  the  air  pump  discharges  into  a  pit  and  the  end 
of  the  air  pump  diffuser  is  not  submerged,  it  will  be  necessary 
to  open  the  steam  primer  before  opening  the  injection  as  other- 
wise air  would  immediately  travel  back  up  the  air  pipe  and  no 
initial  vacuum  could  be  established  by  the  injection  water. 

The  injection  water  which  is  under  pressure  is  usually 
supplied  for  a  few  minutes  only  when  starting  the  condenser, 

18 


for  -after  the  vacuum  is  once  established  the  main  injection 
line  may  be  opened  and  the  pressure  line  closed  and  the  con- 
denser will  draw  its  own  water.  The  usual  custom  in  instal- 
lations of  this  nature  is  either  to  connect  a  water  pressure  line 
in  the  injection  line  between  the  condenser  and  the  main  in- 


fNSINE  ffOOM 
L/ffE 


3/sctt/r*'erf     I" 
>  HOT  weu.  Q_ 


SW//VS  CHECK    VALVE 


/AfLfT  TO  WELL 


Fig.  10 
SPECIAL  ARRANGEMENT  WITHOUT   EXHAUST  VALVE   BETWEEN   CONDENSER  AND 

TURBINE.    A  PRIMING  PUMP  is  USED  FOR  STARTING 

jection  valve,  or  have  an  auxiliary  priming  pump  which  by- 
passes the  injection  valve  (see  Fig.  10.)  In  either  case,  the 
main  valve  is  closed  while  starting  up  until  the  vacuum  is 
established  and  then  opened  before  the  pressure  line  is 
closed. 

19 


The  Air  Pump 

When  the  vacuum  has  been  obtained,  the  air  pump 
suction  may  be  throttled  down.  It  should  be  closed  to  such 
a  point  that  the  needle  on  the  air  pump  suction  gauge  stands 
at  the  red  mark  on  the  dial.  This  dial  is  marked  at  the  proper 
place  as  indicated  by  the  test  of  the  condenser  made  at  our 
Hast  Pittsburg  Shops. 

In  plants  where  there  is  an  excessive  air  leak,  it  may  be 
necessary  to  open  the  air  pump  injection  further  to  maintain 
the  maximum  vacuum,  giving  a  lower  reading  on  the  air  pump 
suction  gauge.  If  it  should  be  necessary  to  do  this  in  order  to 
keep  the  vacuum  produced  by  condenser  to  the  maximum  fig- 
ure, the  following  method  of  procedure  should  be  adopted: 

When  the  condenser  is  running  under  normal  condi- 
tions, that  is,  condensing  steam  from  the  main  unit,  open  the 
air  pump  injection  valve  wide  and  then  gradually  throttle 
down,  in  the  meantime  carefully  observing  the  mercury  col- 
umn which,  of  course,  indicates  the  vacuum  in  the  condenser. 
When  throttling  down,  there  will  be  some  point  at  which  the 
mercury  column  showing  vacuum  in  condenser  will  begin  to 
drop,  say  for  case  of  discussion  that  this  happens  when  1 8"  is 
registered  on  the  gauge  on  the  air  pump  suction,  then  open 
up  air  pump  injection  till  this  gauge  registers  about  2"  less, 
viz.  16".  This  should  be  the  ordinary  setting  of  the  air  pump 
injection  valve  for  this  installation. 

The  air  pump  is  designed  to  handle  twice  the  amount  of 
air  that  should  naturally  come  in  with  the  injection,  but  as  a 
portion  of  the  air  is  held  entrained  and  discharged  to  the  hot 
well,  it  has  been  shown  by  test  that  the  air  pump  is  capable  of 
handling  two  and  a  half  times  the  amount  of  air  liberated  from 
the  injection  water.  This  means  that  the  air  pump  is  quite 
liberally  designed  and  if  the  proper  vacuum  is  not  maintained 
a  disproportion  ably  large  amount  of  air  is  probably  leaking 
into  the  system. 

The  power  taken  by  the  air  pump  is  proportional  to  the 
amount  of  water  allowed  to  pass  through  it.  It  is,  therefore, 
desirable  to  reduce  the  air  leakage  as  much  as  possible,  thereby 
reducing  the  amount  of  water  required  by  air  pump  and,  conse- 
quently, reducing  the  horse  power  required  for  its  operation. 

20 


Regulation  of  Injection  Water 

When  the  amount  of  injection  water  available  is  unlimit- 
ed, the  injection  valve  should  be  opened  as  wide  as  possible  with- 
out flooding  the  condenser  or  causing  the  vacuumbreakerto  open. 

This,  of  course,  assumes  that  care  will  be  taken  not  to 
overload  the  motor  or  turbine  driving  the  pumps,  also  that  the 
injection  water  is  at  a  moderate  temperature  for  with  very 
cold  water,  say  below  40°,  the  increase  in  vacuum  will  be 
small  compared  with  the  increase  of  power  required  to  handle 
the  water  in  the  condenser. 

The  more  water  put  through  the  condenser  the  better, 
of  course,  will  be  the  vacuum.  This  extra  vacuum  gives  the 
main  unit  from  which  the  condenser  is  condensing  the  steam, 
greater  power  and  in  the  case  of  a  turbine  where  a  high  vac- 
uum is  extremely  desirable,  the  power  delivered  at  the  switch 
board  increases  more  rapidly  than  the  power  required  by  the 
condenser  to  discharge  the  additional  amount  of  water.  This 
last  statement  is  not  strictly  correct  as  applied  to  a  reciproca- 
ting engine,  as  in  this  type  of  engine,  any  in  crease  of  vacuum 
over  26",  means  a  very  small  increase  of  power. 

Condenser  Inspection 

The  condenser  has  been  carefully  designed  to  facilitate 
quick  and  thorough  inspection.  A  manhole  at  the  top  allows 
easy  access  to  the  injection  nozzles.  The  nozzles  (Fig.  i 
marked  "  B  ")  are  on  a  plate  which  is  held  in  position  by  three 
slip  bolts  and  a  hinge  bolt.  An  eye-bolt,  not  shown  in  the 
figure,  is  placed  diametrically  opposite  the  hinge  bolt.  By 
putting  a  piece  of  rope  through  the  eye  bolt  and  fastening  it 
to  one  of  the  nozzles  the  plate  can  be  lowered  for  inspection  to 
see  if  any  foreign  matter  is  in  the  nozzles.  These  nozzles 
should  always  be  inspected  a  few  days  after  the  condenser  is 
set  in  operation,  as  pieces  of  gaskets,  sticks  of  wood,  etc.,  are 
apt  to  be  left  in  the  injection  line  when  installing  and  are  de- 
posited on  the  nozzles  by  the  flow  of  water. 

The  discharge  pump  has  a  sight  hole  on  the  volute  and 
the  air  pump  has  two  sight  holes,  one  on  the  top  to  see  if  the 

21 


blades  are  clear  and  one  on  the  side  for  inspection  of  the  water 
distributer  which  is  on  the  inside  of  the  air  pump  wheel.  By 
opening  these  sight  holes  and  turning  the  shaft  by  hand  from 
the  coupling  end,  a  thorough  inspection  can  be  made.  A  large 
manhole  on  the  back  of  the  condenser  body  allows  the  interior 
of  the  discharge  pump  to  be  inspected. 


Location  of  Gauges  and  Method  of  Taking 
Condenser  Readings 

In  taking  readings  to  determine  if  the  condenser  per- 
formance is  satisfactory,  care  must  be  taken  that  gauges  and 
thermometers  are  in  the  proper  place. 

The  main  injection  gauge  should  be  placed  between  the 
condenser  and  the  injection  valve.  The  gauge  should  be  placed 
as  close  to  the  condenser  as  practicable. 

The  air  pump  suction  gauge  should  be  placed  between 
the  air  pump  suction  valve  and  the  air  pump  or  on  the  air 
pump  body  where  a  tap  is  provided  for  it. 

The  discharge  pressure  gauge  should  be  placed  as  close  to 
the  condenser  discharge  pump  as  possible  and  to  get  accurate 
readings  this  guage  should  not  read  to  more  than  30  pounds. 

The  vacuum  in  the  condenser  should  not  be  measured 
by  a  gauge  as  it  is  not  sufficiently  reliable  or  sensitive  for  ac- 
curate work.  A  mercury  column  should  always  be  used  and 
should  be  tapped  into  the  condenser  head. 

Should  a  vacuum  gauge  be  placed  on  the  condenser  care 
should  be  taken  to  locate  it  above  the  point  at  which  it  is  tap- 
ped into  the  condenser,  so  that  all  condensation  in  the  gauge 
pipe  will  drain  back  to  the  condenser. 

The  thermometer  for  measuring  the  temperature  of  the 
injection  water  should  be  placed  in  the  injection  line. 

The  thermometer  for  measuring  the  temperature  of  the 
discharge  water  may  be  placed  in  the  discharge  line  or  in  the 
pump  body  where  a  pipe  tap  is  provided  for  it. 

The  thermometer  for  measuring  the  temperature  of  the 
exhaust  steam  should  be  placed  on  the  top  of  the  inlet  chamber 
of  the  condenser  diametrically  opposite  the  exhaust  steam  en- 

22 


trance,  so  that  no  errors  will  be  introduced  by  heat  being  con- 
ducted from  the  turbine  or  engine  cylinder. 

The  barometer  reading  should  preferably  be  taken  in 
the  engine  room,  but  if  this  is  not  practicable,  a  reading  should 
be  taken  from  the  nearest  barometer  that  is  available.  As 
climatic  conditions  vary  so  much,  a  reading  from  a  barometer 
•ten  miles  from  the  power  plant  would  be  of  doubtful  value. 
The  elevation  must  also  be  taken  into  account  as  a  difference  of 
altitude  of  100  ft.  makes  a  difference  of  one-tenth  of  an  inch  of 
mercury  in  the  pressure  of  the  atmosphere,  consequently  if 
the  barometer  reading  were  taken  on  top  of  a  high  building,  it 
would  have  to  be  corrected  to  the  engine  room  level,  at  the  rate 
of  one-tenth  inch  per  hundred  feet  elevation. 

In  taking  readings  on  a  condenser,  there  are  three  that 
should,  if  possible,  be  taken  simultaneously,  particularly  in 
the  case  of  a  fluctuating  load,  such  as  is  common  in  electric 
railway  service.  These  readings  are  : 

1.  Vacuum  by  mercury  column. 

2.  Temperature  of  exhaust  steam. 

3.  Temperature  of  discharge  water. 

Fig  ii  shows  a  log  sheet  for  a  condenser  test  and  if  a 
test  is  run  and  the  data  sent  to  us  we  are  always  glad  to  an- 
alyze it,  and  give  customers  the  benefit  of  our  suggestions. 

In  testing  an  installation,  make  one  test  on  the  conden- 
ser alone,  that  is,  with  the  main  steam  inlet  and  the  main  injec- 
tion valve  closed;  simply  run  the  air  pump.  Just  before  taking 
readings,  open  the  main  injection  valve  three  or  four  turns  to 
throw  out  all  of  the  hot  water  that  may  be  in  the  condenser, 
close  the  main  injection  slowly,  wait  about  two  or  three  minutes, 
then  take  the  reading  by  mercury  column,  and  the  temperature 
of  the  air  pump  injection  water.  From  these  readings  together 
with  the  barometer  reading  you  can,  by  referring  to  the  table  of 
temperatures  and  pressures  for  water  vapor  here  with,  easily  deter- 
mine whether  or  not  the  condenser  in  itself  is  working  properly. 

Take  the  vapor  tension  or  absolute  pressure  in  inches  of 
mercury  corresponding  to  the  temperature  of  the  water  in  the 
condenser  and  add  this  to  the  vacuum  in  the  condenser,  meas- 
ured in  inches  of  mercury.  If  the  condenser  is  in  good  condi- 
tion the  sum  should  equal  the  barometer  reading. 

23 


Form  .'I;.'  iljllu.  \,i,  U.ll    HIM    I.' IN 


The  Westinghouse  Machine  Co. 


CONDENSER  PERFORMANCE 


Customer. 


State 


Size  Condenser. 
Serial  No... 


Date                                                                     Time 

Load  in  K.  W.  on  Main  Engine  or  Turbine 

Vacuum  at  Condenser  by  Mercury  Column        {A^ 

Barometer 

Temperature  of  Injection  Wafer  "F.                       MEM 

Temperature  of  Discharge  Water   °F                      Ccj 

Temperature  of  Air  Pump  Injection  Water  'F         (Dj 

Temperature  of  Steam  in  Exhaust  line  from             (^r\ 
Engine  or  Turbine  to  Condenser                                 vi/ 

Back  Pressure,  Ibs.  per  sq.  in.  on  Condenser          /O\ 
Discharge  Pump                                                           V^y 

Height  of  Water  in  Condenser  Body  above             /T\ 
center  line  of  Pumps                                                  \£x 

Vacuum  at  Condenser   Injection  Inlet                    (Hj 

Vacuum  at  Air  Pump  Injection  Inlet                    (jj 

Speed  of  Pumps  -  R.P.M. 

Steam  Pressure  -  Lbs.  Gauge 

readings  to  be  taken  at  as  nearly  the  same  time  as  possible,  particularly  E-Aond  C  in  the  order  named. 


Remarks : 


t  Pumps 


'      Readings  to  be  taken  at 
locations  indicated  by  lelttn 


Signature. 


Fig.  11 
LOG  SHEET  FOR  CONDENSER  TESTS 


24 


An  explanation  of  the  table  is  as  follows: 

Water  boils  under  atmospheric  pressure  (30"  barometer) 
at  2 1 2  °  F.  As  the  pressure  is  reduced,  the  temperature  of  the 
boiling  point  is  likewise  reduced.  Therefore,  knowing  the 
temperature  of  water  in  condenser  we  can  easily  get  the  abso- 
lute pressure  in  inches  of  mercury  at  which  it  would  boil.  So 
when  the  air  pump  has  evacuated  the  air  down  to  the  boiling 
pressure  of  the  water,  no  lower  pressure  can  be  gotten  as  the 
water  goes  off  into  steam.  Therefore,  if  we  take  the  vacuum 
in  the  condenser  in  inches  of  mercury,  plus  the  pressure  due 
to  the  temperature  of  the  water  in  the  condenser  the  sum 
should  equal  the  barometer  reading. 

For  example: 

Tern,  of  water  in  condenser =73°. 
Vac.  by  mercury  column  — 28.72. 
73°  water  corresponds  to  0.812  inches  of  mercury. 

(See  table  page  26). 

0.812  +  28.72=29.532  which  should  be  equal  to  the 

barometer  reading. 

If  the  barometer  is  lower  than  29.532"  there  has  been 
some  error  in  the  readings  taken.  If  the  barometer  is  higher 
than  29.532"  there  is  an  air  leak  in  the  condenser. 

AIR  LEAKS 
How  to  Find  Them  and  How  to  Remedy  Them 

If  air  leakage  is  suspected  in  a  condenser  installation, 
it  will,  of  course,  only  be  necessary  to  look  for  it  in  parts  of 
the  system  subject  to  vacuum.  Referring  to  Fig.  12,  the 
parts  subjected  to  vacuum  are  shaded. 

Water  Injection  Line 

Run  the  condenser  with  the  air  pump  only;  that  is,  with 
main  exhaust  and  injection  valves  closed,  and  note  the  vacuum 
obtained.  Then  open  the  injection  valve  and  after  running  a 
few  minutes  if  the  vacuum  has  dropped  more  than  3-10  or  4-10 
of  an  inch,  then  there  is  a  leak  in  the  injection  line.  A  drop  of 
3-10  to  4-10  of  an  inch  is  to  be  expected  as  there  is  usually  2% 

25 


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26 


of  air  by  volume  in  any  water  and  this  air  expands  when  it  has 
entered  the  condenser  and  causes  a  drop  in  the  vacuum. 

There  are  usually  three  sources  of  leakage:  the  valve 
stem  packing,  the  line  itself,  or  at  the  cold  well,  due  to  in- 
sufficient submergence  of  the  injection  line. 


Fig.  12 

DIAGRAM   SHOWING   PORTIONS  OF  TURBINE  AND   CONDENSER  UNDER  VACUUM 

To  test  the  injection  line,  tap  in  a  vacuum  gauge  close 
to  the  injection  valve  on  the  side  towards  the  cold  well. 
With  the  condenser  drawing  about  its  rated  amount  of  water, 
take  a  reading  and  then  close  the  injection  valve  and  take 
readings  at  intervals  of  several  minutes.  The  difference 
between  the  readings  taken  directly  before  and  after  closing 
the  valve  will  indicate  the  friction  head  in  the  water  line  in 
feet,  as  one  inch  of  vacuum  corresponds  to  about  one  foot  head 
of  water.  Make  two  tests,  one  test  with  the  condenser  running 
and  the  other  with  the  condenser  stopped  directly  after  closing 
the  injection  valve,  as  the  main  injection  valve  may  leak  and 
a  comparison  of  the  two  readings  will  show  this. 

If  the  injection  line  is  tight  then  there  may  still  be  a 
large  amount  of  air  admitted  to  the  condenser  by  too  small  a 

27 


submergence  of  the  injection  pipe  in  the  cold  well.  It  should 
always  be  submerged  at  least  four  feet  and  preferably  more, 
otherwise  eddys  or  whirlpools  wrill  form  through  which  air 
will  pass  into  the  injection  pipe.  This  can  be  stopped  tem- 
porarily by  building  a  floating  platform  around  the  pipe 
which  will  break  up  the  whirlpool,  but  the  proper  remedy 
would  be  to  increase  the  submergence. 

Should  the  air  pump  suction  line  take  its  water  from 
the  main  injection  it  would  be  necessary  in  testing  the  tight- 
ness of  the  main  injection  line  to  close  the  air  pump  water 
valve  immediately  after  closing  the  main  injection  valve  and 
then  proceed  as  before. 

When  installing  a  condenser,  it  is  always  best  to  leave 
the  injection  line  uncovered  until  it  is  certain  that  it  does  not 
leak  at  any  point. 

Should  the  vacuum  in  the  condenser  surge,  that  is 
repeatedly  drop  two  or  three  inches  and  recover  itself,  it  is  an 
indication  that  the  condenser  first  gets  a  gulp  of  air  and  then 
a  gulp  of  water  although  the  line  may  be  perfectly  air  tight. 
It  is  occasioned  by  air  pockets  forming  in  the  injection  line 
due  to  uneven  laying  of  the  pipe.  Thus,  if  the  line  is  laid 
with  "tips  and  downs,"  a  pocket  of  air  will  form  at  the  crest 
of  each  rise  due  to  natural  separation  of  air  and  water  when 
under  a  vacuum.  These  pockets  of  air  going  to  the  condenser 
spasmodically,  cause  the  surging,  and  sometimes  even  cause  the 
condenser  to  lose  its  vacuum  entirely.  This  can  be  remedied  by 
connecting  a  small  pipe,  say  about  one  inch,  into  the  injection 
line  at  the  highest  point  and  leading  it  to  the  condenser  body, 
inserting  a  valve  close  to  the  condenser.  This  one  inch  line 
will  take  off  the  air  as  it  collects  and  stop  the  surging. 

Condenser 

Proceed  as  described  under  "Location  of  Condenser 
Gauges  and  Method  of  Taking  Condenser  Readings"  on  pages 
23  to  25.  In  addition,  fill  up  the  exhaust  pipe  to  condenser 
with  water  in  order  to  effectually  seal  and  stop  any  air  leak 
through  the  main  exhaust  valve.  Also  make  sure  that  there 
is  no  air  leak  through  the  exhaust  valve  stem  packing. 

28 


Atmospheric  Relief  Valve 

This  valve  may  not  be  properly  sealed  with  water  and 
it  may  not  seat  correctly.  This  can  readily  be  determined  by 
running  the  main  unit,  preferably  under  no  load,  throw  in  the 
condenser  and  then  taking  off  the  cover  or  cap  on  the  relief 
valve,  see  if  it  is  in  operative  condition.  Also  see  that  the  valve 
stem,  which  in  the  case  of  a  horizontal  valve,  comes  from  the 
vacuum  side,  does  not  leak  around  the  gland  or  stuffing  box. 

Exhaust  Pipe 

In  some  cases  the  exhaust  pipe,  which  is  of  cast  iron, 
has  blow  holes,  sand  holes  or  other  imperfections.  The  best 
way  to  locate  them  is  to  close  the  main  exhaust  valve  and  fill 
the  exhaust  line  with  water  and  any  hole  will  quickly  show 
up.  Small  holes  can  be  easily  stopped  up  with  asphaltum 
paint  applied  while  the  line  is  under  vacuum.  Large  holes 
should  be  drilled  out  and  plugged. 

At  the  lowest  point  in  the  exhaust  pipe  there  are  usual- 
ly attached  two  check  valves  in  series  that  permit  any  water 
that  accumulates  in  the  line  while  the  engine  is  standing  idle 
or  running  non-condensing,  to  drain  out.  There  may  be  for- 
eign matter  in  these  valves  or  they  may  not  close  properly. 
This  is  easily  determined  by  breaking  the  joint  outside  of  the 
valves  and  screwing  on  an  elbow  or  some  sort  of  riser  so  that 
the  valves  may  be  water  sealed.  Fill  the  riser  with  water  and 
with  the  condenser  under  vacuum  observe  if  the  water  disap- 
pears. Of  course,  if  it  disappears  there  is  a  leak  and  a  simple 
way  to  stop  it  is  to  put  about  a  six  inch  riser  outside  of  the 
valves  and  into  the  bottom  of  this  riser  lead  the  drain  from 
the  atmospheric  relief  valve  seal,  and  from  the  top  of  this 
same  riser  lead  off  the  overflow.  The  drain  from  the  atmos- 
pheric relief  will  thereby  keep  the  check  valves  sealed. 

Air  in  the  Steam 

This  is  often  occasioned  by  the  boiler  plant  not  having 
a  good  feed  pump.  In  the  case  of  a  reciprocating  feed  pump 
the  engineer  in  charge  may  not  keep  the  pump  glands  well 

29 


packed.  It  is  particularly  noticeable  when  the  pump  will  go 
a  full  stroke  quickly  and  is  easily  seen  to  be  drawing  in  air 
rather  than  water.  In  a  well  designed  plant  the  feed  water 
heater  is  usually  above  the  pumps  so  that  the  water  flows  by 
gravity  and  the  tendency  to  draw  in  air  is  consequently  dimin- 
ished. After  the  air  is  drawn  in  it  is  compressed  and  forms  an 
emulsion  with  the  water  and  is  in  that  state  forced  over  into 
the  boiler,  and  eventually  to  the  condenser.  This,  of  course, 
impairs  the  vacuum  in  the  condenser  and  it  cannot  be  im- 
pressed too  strongly  on  the  operating  engineer  that  the  vacuum 
depends  a  great  deal  on  the  way  he  keeps  his  boiler  plant  up 
to  date  and  that  a  few  cents  spent  in  packing  will  repay  him 
in  dollars  in  power  delivered  from  the  main  unit. 

Various  Points  of  Leak 

The  expansion  joint  may  be  cracked. 

With  a  reciprocating  engine  the  piston  rod  packing  may 
be  in  bad  condition. 

The  vacuum  breaker  on  the  condenser  may  have  sedi- 
ment under  the  seat.  The  valve  should  be  tight  enough  to 
hold  water  and  if  not,  grind  it  in  with  a  little  emery. 

If  the  main  unit  is  a  turbine,  look  for  leaks  in  the  in- 
termediate and  low  pressure  equilibrium  pipe;  the  gland  drain 
where  it  goes  inside  of  the  turbine  exhaust  nozzle;  this  latter 
point  can  be  examined  by  breaking  the  drain  where  it  leaves 
the  exhaust  nozzle,  plugging  it  and  filling  the  line  with  water 
up  to  the  turbine  gland;  if  the  water  disappears  there  is  a  bad 
connection  inside  of  the  exhaust. 

The  turbine  glands  should  be  sealed  with  the  coldest 
water  obtainable,  for  if  the  gland  water  is  warmer  than  the 
temperature  of  the  vacuum,  the  water  will  go  off  into  steam 
and  will  not  effectively  seal  the  glands. 

A  rough  determination  of  the  amount  of  air  leakage  in 
the  turbine  and  exhaust  pipe  as  a  whole,  can  be  made  in  the 
following  manner : 

Have  the  turbine  running  under  no  load,  the  con- 
denser condensing  the  steam  from  it  and  then  close  the  steam 
valve  to  the  turbine.  As  the  turbine  is  up  to  speed  and  run- 

30 


ning  in  a  vacuum  it  will  maintain  its  speed  and  seal  the 
glands  for  at  least  five  or  more  minutes.  Now  by  closing  off 
the  main  injection  the  condenser  should  be  able  to  maintain 
as  high  a  vacuum  running  this  way  as  if  the  condenser  were 
running  by  itself,  that  is,  with  the  main  exhaust  valve  closed. 

In  General 

The  exhaust  piping  is,  of  course,  installed  in  a  cool  con- 
dition and  the  gaskets  become  soft  when  the  piping  is  heated. 
Therefore,  it  is  best  to  run  the  main  unit  non-condensing  and 
tighten  up  all  joints  well  while  hot.  Also  the  atmospheric 
relief  valve  will  put  a  slight  back  pressure  on  the  exhaust  line 
and  any  bad  leaks  will  show  up. 

After  tightening  joints,  paint  the  whole  joint  with  as- 
phaltum  paint.  In  painting  a  joint,  paint  the  whole  flange 
including  the  bolts  and  nuts.  It  is  not  sufficient  to  paint  just 
the  outside  of  the  flange  alone,  as  air  may  leak  under  the  head 
or  nut  of  the  bolt  and  travel  down  the  bolt  hole  as  all  bolts 
have  about  */$ "  clearance  in  the  holes. 

The  best  method  of  locating  a  leak  is  to  put  the  part 
being  tested  under  a  water  pressure  and  look  for  water  drips. 
Another  method  is  to  get  the  line  under  a  vacuum  and  test 
joints  with  a  candle  flame.  The  water  test  is  preferable  as  it 
will  show  up  not  only  leaky  joints  but  also  blow  holes  and 
sand  holes  in  the  pipe  itself,  which  one  would  not  know  where 
to  look  for  in  applying  the  candle  flame  test. 


The  Westinghouse  Machine  Co. 

General  Offices  and  Works 

East  Pittsburg,  Pa. 


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SALES  OFFICES 

165  Broadway 

Chandler  Building 

131  State  Street 

171  La  Salle  Street 

1102  Traction  Building 

New  England  Building 

Hunt,  Mirk  &  Co.,  141  Second  Street 

512  McPhee  Building 

Westinghouse  Building 

1003  North  American  Building 

Chemical  Building 

-     G.  and  O.  Braniff  &  Co. 


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LD  21-100w-7,'39(402s) 


6305 


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